The less mental and physical activity your dog has, the more mischief he tends to get into.
To help counteract his boredom, consider teaching your dog some new activities that will exercise both his brain and his body. One activity I like is the puppy push-up. It is fun for you and your dog and helps to reinforce the bond between you. When your dog gets pushy for attention and won’t leave you alone, have him do a few push-ups. A push up is a sit, followed by a lie down, and then back to a sit, with this sequence repeated several times. There are numerous videos on the web teaching puppy push-ups. This is one of my favorites.